Heat-exchanging apparatus



Nov. 4, 1930. v s, JR 1,780,294

HEAT EXCHANGING APPARATUS Filed Feb. 1, 1929 3 Sheets-Sheet l lll lllllIIV/IIIII ll llllalllllull 3 Sheefs-Sheet 2 A. H. DAVIS, JF

HEAT EXCHANGING APPARATUS Filed Feb. 1. 1929 Nov. 4, 1930.

WITNESSES Nov. 4, 1930. A. H. DAVIS, JR

HEAT EXCHANGING APPARATUS 5 Sheets-Sheet Filed Feb. 1, 1929 INVENTOR WPatented Nov. 4, 1930 I UNITED STATES PATENT OFFICE- ABCHIBALD H. DAVIS,,JR, PITTSBURGH; PENNSYLVANIA, ASSIGNQR TO SHAW- PERKINS MANUFACTURINGCOMPANY, OF PITTSBURGH, PENNSYLVANIA, A CORPO- v RATION OF PENNSYLVANIAnsnr-nxcnnneme APQPARATUS Application filed Februaiy 1, 1929. seriai'm.336,746. 7

This invention relates to heat exchanging apparatus and especially toapparatus for preheating air from hot waste gases.

Regenerative preheaters are bulky, expensive to install, and requiremechanism for alternating gas and air flow. The reversing mechanismrequires adjustment and attention, and, through faulty operation, it maycease to function, or do so improperly, thus disturbing operation of theunits with which it is associated. Although compact, the plate type ofheat exchanger is disadvantageous because replacement of'the plates isdifiicult,

soot accumulation may be high and its removal diflicult. The mostefl'icient heat transfer has been secured by means of tubular heat Theseprovide turbulent gas tubular heaters do not permit standardization, sothat each installation is a separate job and the apparatus is notreadily combinable to provide various sizes. Furthermore, theirconstruction is usually such that expansion and contraction may causeserious stresses to be set up.

An object of the invention is to provide tubular heat exchangingapparatus which embodies all of the advantages and m1n1 mizes thedisadvantages of prior tubular apparatus of this type. which is compact,of sime ple and relatively inexpensive COIIStIUCtIODp in which the tubesare grouped in standardized radiator units arranged sectionally toprovide for easy removalof the individual units without materialdisassembly of the apparatus and which are readily combinable to giveapparatuses of different sizes, and in which all removable parts arereadily; acces;

sible.

Another object is to provide such heat exchanging apparatus'in which theradiator units are built from tubes of generally elliptical crosssection, to provide minimumdepov sition'of soot, decrease res1stance togas flow,

and provide more elficient heat transfer surface than has been presentin heat exchanging apparatus using round tubes.

. A further object is to provide apparatus of the type referred to whichprovides for diiferential expansion of the -radiators and framework, andfor expansion and contraction of the unitary tube headers.

The preferred embodiment of the invention is shown in theaccompanyingdrawings,

in which Fig.1 is a front elevation; Fig. 2 1S a plan View of theapparatus shown in Fig. 1;

Fig. 3 is, a fragmentary perspective view showing a radiator unit 7 (inthe lower right handcorner) partly withdrawn; Fig. 4 is a partial sideelevation and transverse section taken on line IVIV, Fig. 1; Fig. 5 isan enlargedJvie'w of one of the corners of the apparatus shown in Fig.1; Fig. .6 is a vertical section at a corner-taken on line VI-VI, Fig.v5; Fig. 7 is a horizontal section through a corner taken on lineVII-VII, Fig. 5; and i Fig. 8 is an enlarged sectional view showing themanner of connecting theradiator units in the apparatus, taken on lineVIIIVIII, Fig. 1.

Having reference to the drawings, the apparatus provided by theinvention-comprises a framework and superimposed radiator units eachcomprising a plurality of parallel heat exchanging tubes.

' The frame is preferably built up from structural sections, as shownespecially in Figs. 1 to 4. The apparatus shown comprises vertical sidechannels 1 to which connecting plates 2 disposed across their ends arejoined in any suitable manner, as by weldin n The top and bottom of theframe work are formed by longitudinal channels 3 and transverse channels4; connected at their abutting ends by angles 5 bolted thereto. Thechannels 4 are preiierably connected to plates 2 by welding. .Thisstructure provides an openboxlike frame work, and air and gas ducts, not

shown, may be readily connected to the opposed openings formed betweenchannels 3 and 4 and between channels 1 and plate 2, the outer legs ofthe channels acting as flanges for that purpose. To provide a continuousperipheral duct-connecting flange around the openings defined bychannels 1 and plates 2, angles 6 are welded to the outer edges of theplates.

In accordance with the invention the heat exchanging tubes are groupedinto a plurality o f individual radiator units 7. A suitable I number ofthese units are carried in the framegenerall elliptical cross section,because such tubes w en disposed with the major axis of the sectionparallel to the direction of gas flow, offer less resistance to flow,decrease soot deposition and increase the effectiveness of soot blowers,as compared with round tubes. Furthermore, they can be placed closertogether than round tubes, which makes .the units'more compact, causesthe gas to scrub substantially the entire tube surface, and brings airor other media passed through the tubes into contact with a greater areaof heat exchanging surface.

The radiator units may be constructed from tubes and headers in anydesired manner, but in the preferred embodiment there are used radiatorsof the type disclosed in United States Patent No. 1,320,652 to C.Sonneborn,

dated Nov. 4:, 1919. According to that patent, the ends of oval tubes 8are welded to panshaped headers 9 having an outwardly bent peripheralflange 10, Figs. 4 to 8. These headers are made by pressing sheet metal,and for ease of Withdrawal from the dies, the sides of the pan aresloped from the bottom to the flange. As hereinafter described, thissloping construction is made use of in taking care of header expansion.possesses advantages of simple, sturdy, and relatively inexpensiveconstruction, and there are no mechanical joints to loosen or otherwisecause trouble.

These radiator units are mounted in the framework one above another, togive sectional stacks from which any units may be laterally withdrawnwhen necessary. A single stack of units may be used, oras in the formshown, two or more stacks may be built up side by side.

In the embodiment shown in the drawings, the radiator units aresupported as follows, this construction being applicable to both singleand multiple stack apparatuses. Railsupporting members 11, preferablyangles, are disposed Vertically on each side of two opposed openings,for connection to horizontal guide rails 12 spaced apart vertically toreceive the radiator units 7, as shown particu- This form of radiator.

larly in Figs. 2 and 4. Members 11 are preferably disposed in theopenings formed by channels 1 and lates 2, and the angles, which extendthe full height of the opening, are placed with one arm against the webof the channel and the other arm projecting into the opening.

The radiator units are placed in the framework by insertion through theopenings between channels 1-1 and 3-3 from the right or left of Figs. 1and 2, the headers 9 and flanges 1O slidably engaging rails 12. A unit 7partially withdrawn is shown in the lower right-hand portion of Fig. 3.In order to provide for read withdrawal of the units past angles 11 anchannels 1, the rails 12 are spaced from the angles by spacer blocks 14,as shown in the corner assembly of Fig. 7 Short sections 15 of rail arepositioned vertically between adjacent horizontal rails 12 on each sideof the headers, for use in looking the units in position. After theunits have been set in place, they are connected to rails 12 and 15 byclamps 16 which engage adjacent edges of the headers of two contiguousunits. These clamping members are preferably of channel form, the innersurfaces of their legs being tapered outwardly, as shown in Figs. 6 to8. In the apparatus shown, the horizontal clamps and the centralvertical clamps are bolted directly to the rails. The

vertical clamps at the side of the apparatus are bolted to rails 15 bbolts 15* engaging both the angles 11 and t e clamps. Horizontal rails12 are connected to angles 11 by bolts 12. To remove a unit, bolts 15are taken out from its outer side clamp 16, and the center side clampand horizontal clamps are disconnected, leaving rails 12 supported bybolts '12.

. It is desirable to provide means for permitting free expansion andcontraction of the headers and at the same time to provide a gas-tightseal and rigid construction. Preferably, this is accomplished byrounding the flange-engaging edges of the vertical and horizontal rails,the radius of curvature being substantially that between flange 10 andthe face of header 9. When the clamps are bolted into place, the taperedflange-engaging surfaces of the clamps wedge the flanges and railstogether to form a gas-tight fit, and due to the slope of the sides,this portion of the header is spaced from both the legs of the clamp andthe rail, so that it can move in expanding and contracting. Althoughthis construction will ordinarily be sufliciently gas tight, resilientpacking material may be used if desired.

The spaces between the ends of the clamping members are filled in byplates 17 of appropriate shape, bolted to the rails. These plates alsomake gas-tight fit and prevent intermixing of gas and air.

It is desirable to provide for differential I expansion of the frame andradiator units, or tubes, and this is accomplished most simply bybolting the angles 11 at one end of the framework to channels 1 by meansof bolts 20, the angles at the other end being free to slide against theface of the channels, as seen best in Figs. 2 and 7.

When used for preheating air from waste gases, it is usually desirableto pass the air through the tubes and gases over them. To that end, airducts, not shown, are connected to the openings defined by channels 1and strains being placed upon the tubes or headersupon their expansionor contraction.

Although especially adapted for use in preheating air for power boilersor gas or oil furnaces, by the heat contained-in gases of combustionfrom the boiler. the apparatus is applicable for air conditioning, andgenerally to transfer of heat from any fluid medium to another.

I claim: 1

1. Heat exchanging apparatus comprising a framework, rails supportedhorizontally in plates 2; and gas ducts are similarly con two oppositeends in the framework, radiator nected to the openings on opposite sidesformed between channels 3 and 4. The two remaining sides, defined bychannels 1 and 3, are most suitably closed by flanged plates bolted tothe channels. These sides may be -lagged if desired. Any suitable formof soot blower may also be installed in these side plates.

It will be seen that through the use of radiator units of standardizedsizes, apparatus provided by the invention .can'be readily constructedto any desired he1ght,,w1dth, and tube length. An appropriate number ofunits may be built up in a single apparatus, or two or more standardassemblies may be superimposed and bolted together, the apparatusdescribed being especially adapted for such construction. Likewise, theuse of units of different width, and the constructionin a single or inmultiple stacks gives flexibility in assembly to desired widths.

In using the apparatus as described above, with air passed through thetubes, all parts to be removed are accessible from the outside of theapparatus and from within the air ducts. This makes for'very easyreplace ment of units and eliminates corrosion of the bolts, clamps. andsimilar parts.

In prior apparatus of this type, the tubes were expanded into the sidewalls during construction, this being generally done in its1nstallation. Likewise the replacement of defective tubes was slow andtedious' In thenew apparatus, the side plates are removed, and uponremoval of the clamps retaining the unit containing the faulty tube, theun1t may be easily withdrawn. and a new unit inserted.

This materially reduces the amount of dis-' nnits comprising paralleltubes and headers connected to the ends of the tubes disposed in theframe work with the headers slidably supported between the adjacentrails to be individually laterally removable from the framework,vertical bars positioned between the rails at the ends of the headers,and clamping members engaging said headers removably connected to saidrail members and bars, the rails at one end of the apparatus beingadapted to move in the framework to permit expansion of the radiators.

2. Heat exchanging apparatus comprising a framework built fromstructural section members, angle irons vertically positioned in eachside of two opposite ends of the framework, a plurality of horizontalrail members connected at their ends to said angle irons, radiator unitscomprising parallel tubes of generally elliptical cross sectionand'headers connected to the ends of the tubes, the units ,beingpositioned one above the other in the framework with the headersslidably sup portedbetween the adjacent rails to be individuallylaterally removable from the framework, clamping members engaging thehorizontal edges of the headers removably connected to the rail members,bars vertically disposed between the rails at the sides of the headers,and: clamping members engaging the sides of the headers removablyconnected to said bars. the angles at one end of the framework beingconnected to the framework, and those at the other end being free tomove in the framework to permit differential longitudinal expansion andcontraction between the radiators and framework.

3. Heat exchanging apparatus comprising a framework composed ofstructural section members, angle iron vertically positioned in eachside of-two opposed openings in the framework, horizontally positionedrail members connected at their ends to said angles and spaced therefromby spacer blocks, interchangeable radiator units each comprisingparallel tubes of generally elliptical cross section and flanged headersconnected to the ends of. the tubes disposed one above .another in theframework, the headers being slidably supported between structioneliminates the danger of undue the adjacent rails and the flanges of theheaders bearing against the exterior surfaces of the rails, clam mmembers eng ing ad- I jacent horizontal efges of the hefiers removablconnected to the rails,bars disposed vertical between the rails at thesides of the hea ers and clamps engagingthe sides of,the headersremovably connected to the bars, the angles at one end being connectedto the framework and those at the other end bein' free to move, saidunits being individua lylaterally removable from the framework uponremoval of the vertical and horizontal clamping members which hold it inposition. f Y

4. Heat exchanging apparatus accordin to claim 3, the corners of saidrails an bars in contact with the flangesbeing rounded for engagementwith theiflange, and said clamping members having'taperedflangeengaging'arms adapted to. Wedge the flanges of adjacent headersagainst the rounded edge of the rails and bars, -.the sidesofthe headersbeing freeto move-betweenthe rail and flange arm upon expansionor'contraction of the header.

5. Heat exchanging apparatus comprising astructural section framework,angle iron's vertically positioned in each side .0 tWoop-' posed ends ofthe framework,fhorizontal guide rails connected at their ends to saidangle irons, interchangeable radiator units each comprising paralleltubes of generally elliptical cross section and flanged headersconnected to the ends of the-tubes disposed one above the other in saidframework with the headers being slidably supported between the adjacentrails and the flanges'being in contact with the external side; of therails, bars disposed "crtically between the rails at the sides of theheaders, the edges of the rails and bars in contact with the headersbeing rounded for engagement' with the flange, and clamping membersengaging adjacent edges of adjacent flanges removably connected to therails and bars said clamping members comprising channels having'arms theflangeengaging surfaces of which are tapered to permit movement of thesides of the headers between the rails and said arms;:the=-outsidevertical clamping members being also clamped to the angle irons, theangles. at one end being free to move with respect to the framework andthose at the other end being connected to the framework, and all of theconnections being accessible from the outer side of the headers. wherebythe units are individually laterally removable from the framework.

6. Heat exchanging apparatus comprising a structural section framework,angles vertically positioned in each side of two opposed ends of theframework, horizontal guide rails connected at their ends to saidangles, a plurality of radiator units each prising ticalcross sectionand flanged headers connected to the ends of the tubes, said units beinginserted from opposite sides of the framework with the flanged headersslidably supported between the adjacent rails to form two banks ofsuperimposed units, bars ver-.

tically dis osed between the rails at the sides of the hea ers, theedges of the rails and bars in contact with the headers being roundedfor enga ement with the flange, and cla mpi ng mem ers engaging adjacentedges of adacent flanges removably connected to the rails and bars saidclamping members comchannels havin arms the flangeengagin surfaces of wich are tapered to permit t e sides oftthe headers to move between saidarms and rails upon expansion or contraction of the headers, the outsidevertical clamping members being also clamped to the angle irons, theangles. at one end being free to move with respect to the framework andthose at the other end being connected to theframework, and all of theconnections being accessible from the outer side of the headers, wherebythe units are individually laterally removable from the framework. Y

P In testimony whereof, I sign my name. ARCHIBALD- H. DAVIS, JR.

comprising parallel tubes of generally ellip- Y

